ADA4430-1

Rev. A | Page 13 of 16

USABLE INPUT VOLTAGE RANGE

The output voltage range of the ADA4430-1 limits its usable

input voltage range. The lower end of the input range is

typically 0 V. The upper end of the usable input voltage

range is calculated as

where:

SAG CORRECTION FREQUENCY RESPONSE

When using the SAG corrected circuit, the gain from the input

to the immediate output of the ADA4430-1 is ×2.5 (≈8 dB) at

extremely low frequencies where the outer feedback loop

formed by the 22 μF capacitor effectively opens (see Figure 29)

and exhibits a second-order peak of approximately 11 dB in the

neighborhood of 5 Hz. This gain is approximately 7.5 dB at

30 Hz. The extra gain must be accounted for when considering

low frequency input and output signal swings to keep them

within their specified limits. The gain from the ADA4430-1

input to the load side of the 47 μF capacitor does not exhibit

this behavior, rather it appears more like a single-pole high-

pass response. Figure 32 illustrates the SAG frequency response

immediately at the ADA4430-1 output and at the load side of the

47 μF capacitor.

12

10

8

6

4

2

0

–2

–4

–6

–8

–10

1

10

100

1000

100000

10000

FREQUENCY (Hz)

AT ADA4430-1 OUTPUT

AT LOAD SIDE OF 47µF CAPACITOR

Figure 32. SAG Corrected Frequency Response at ADA4430-1 Output and

at the Load Side of the 47 μF Capacitor